ARRAYED WAVEGUIDE GRATINGSOperation PrincipleOperation Principle (contd ..)Operation Principle (contd..)FunctionsWDM de(multiplexing) and OADMOptical Filter [7]Optical Filter (contd.. )Optical Delay Line [4]AWG ChipReferencesARRAYED WAVEGUIDE GRATINGS-By Shodhan Shetty ECE-E641Operation PrincipleFree Propagation Regions (FPRs) Arrayed WaveguidesAWG is a complex optical circuit contained on a glass-silicon wafer about 1 or 2 inches in diameterOperation Principle (contd ..)Application of Fresnel-Kirchoff diffraction integral to one of the FPRs in an AWGWRA( )Operation Principle (contd..)Fresnel-Kirchoff diffraction integralFree Spectral Range   xxRnxjdARjxUe2,NeffcFSRl.2l=Optical path length difference between adjacent array armsHere,FunctionsWDM de(multiplexing) [1]OADM [2]Wavelength Routing Signal Processing Dispersion Compensation [3]Optical True-time delay lines [4]Optical Filters [5]Femto-second pulse train generation [6]Specifications required:Channel Spacing Pass band Shape Adjacent Channel CrosstalkFree Spectral RangeWDM de(multiplexing) and OADMOptical Filter [7]Optical Filter (contd.. )Optical Delay Line [4]Here, d is distance betweenAntenna Array elementsAWG ChipBare AWG chipA packaged Arrayed waveguideGrating optical mux/demux moduleReferences[1] H. Yamada et al, "Measurement of Phase and Amplitude Error Distributions in Arrayed-Waveguide Grating Multi/Demultiplexers Based on Dispersive Waveguide", Journal of Lightwave Technol., p.1309 (2000)[2] Y. Tachikawa, Y. Inoue, M.Kawachi, H. Takahashi, and K. Inoue,”Arrayed-waveguide grating add-drop multiplexer with loop-back optical paths,” Electron. Lett., 1993,29,pp. 2133-2134[3] Michael Parker, Stuart walker,” Arrayed waveguide gratings, fiber Bragg gratings, and photonic crystals: An Isomorphic Fourier transform light propagation analysis,” IEEE journal of selected topics in quantum electronics, vol. 8, pp. 1158, 2002[4] B. Vidal et al, “Novel Dispersion-based optical delay line using Arrayed waveguide grating for antenna beamforming applications [5] K. Okamoto,” Recent progress of integrated optics planar lightwave circuits,” Optical quantum Electron., vol. 31, pp. 107-129,1999[6] D.E. Leird, A.M. Weiner et al, “Generation of high repetition rate WDM pulse trains from an Arrayed waveguide grating,” IEEE PTL, vol. 13, pp. 221, 2001 [7] Van Thourhaut et al,”Novel Geometry for an Integrated channel Selector,” IEEE Jour. of sel. Topics in Quantum